Masking or screening device for lamps



Sept. 19, 1944.

V. HARTLEY MASK DIG JR SCREENING DEVICE FOR LAMPS Filed April 18, 1942 2 Sheets-Sheet 1 v. HARTLEY MASKING OR SCREENING DEVICE FOR LAMPS 2 W t f a M 4 r a y s t 8 6 h s 2 u m m "w 2. Q n n1 9 n H v 1 n a I I 1 I I Z 1 m 1 i w n A u d f 9 l i F Patented Sept; 19, 1944 MASKING on SCREENING DEVICE FOR Vincent Hartley, Greenfield,- England Application April 18, 1942, sell-mime.- 439,46011 In Great Britain October.6',-1941 c I 8 Claims. (01. 249,484)

' This invention relates to light-screening devices having as: theirobject'the controlling of the direction of light rays from a light source such'as 'an electric lamp. "The more immediate application of the invention'is to the head lamps of motor road vehicles,:either as' a-s'afety device or-mask during light-restriction conditions (e; g. in wartime) 'or merely as an anti-dazzle device at anytime; but the invention is equally applicable-to other uses where a non-dazzle beam of light of'acontrolled cross-section is required, to give adequatevision topersons behind the device whilst the actual light source is largely concealed from the vision of persons in front of the device. Instances, among mafiy,-where the invention may find a use other than on road vehicles are, in street lighting, in ships lighting and in the interior lightingof buildings.

- One object of the invention is to provide a device which fwillfallowfthe maximum emission of light consistent withthe nature of control require'd, which will give a long beam of lightfand which may in some of its forms be of simple constructio'n'adapted for rapid production by a large proportion of I semi-skilled labour. A lightscreening device according to this invention, applied to a motor vehicle headlamp, is capable of entirelyeliminating dazzle to oncoming persons in normal riding orwalking positions, whilst allowing astrong light beam to be projected forwardly and downwardly on to the road for a distance well beyond the minimum required for safe driving j The invention relates to devices'of the known type in-which light from an aperture is excluded from a-particular zone (for example from above a horizontalirplane) by being-caused to pass between spaced louvres, plates or bafiles (hereinafter referred to generically as louvres) immediwhich the louvres are connected together at three Y points only, two at the rear and one at the front of the assembly, some at least ofthe connections being comprised by flanges on the louvres enterand being held by U-sectional gripping and spacing members, and at least one of the connections being IproVidedby the louvres themselves. 1 Usually the louvres will be connected to eachother'atithe rear corners, and at thecentre of their front edges; Means will be provided on 7 or in association with e louvres to prevent the light impinging on their upper faces, thuspre-- venting reflection into the prohibited zone. Such anuarrangement, whilst preserving all the necessarysafety factors by ensuring that no light is directed upwardly, allows of a much wider beam of'light than if the front corners were obstructed, V

and therefore gives better lightat the sides. of the rro'ad-xwhere, at times,;itis particularly required": assembly-in; use, issecured to .a suitablexapertured carrier plate, so as to control light passing towards the louvres throughthe aperture, and is covered. or roofedvover by: a suitable =cowl; adiifusingglass ispla ced behind the assembly of louvres and in front of the;light next above it.: "Ihe front portions of the louvres are also clamped collectively between two members co-operating with a cowl-above them, and with the uppermost and lowermost louvre respectivel-y: In addition to being flanged at their edges the louvres will usuallyhave one or more upstanding ribs or ridges extending fromside to side and these may'comprise pressed-up flanges arranged parallel with each other 'and'with the front edge. Usually allthe louvres of an assem bly will be of identical form. r 5 'The cowl'i's preferably made separately from side wings enclosing the rear portions'of the sides offthe louvres, and overhangsthose wings, but it may, if desired, be made in one with those wings or the wings may be omitted. The several parts may usefully be securedtogether by spot welding. v

In'an' embodiment 'of the invention, already reduced to practice, andadapted for a motor vehicle head lamp, there isa circular apertured back plate flanged peripherally to-fit the usual head lamp bezel'in place of'the glass lens; as assembly of 10 louyres' (or thereabouts) flanged hpwardly all around and with well-rounded front held against the back plate behind the louvres, 1

all the parts except the glass being sheet metal stampings and pressings.

In all cases for a road lamp or vehicle lamp the assembly of louvres shouldbe mounted so that the louvres have a slight downward inclination in the direction away from the light source, to ensure that a line joining the upper rear edge Y of one and the lower front edge of the next one higher will not extend above the horizontal plane in aforward direction. I 7

In its most limited form the invention is characterised accordingto the example hereinafter described in detail with reference to the drawings.- r r The invention is illustrated in the accompanying drawings, wherein:

Fig; 1 is a front perspective view of a head lamp mask according to the embodiment above described; r

Fig. 2 is a vertical cross-section through the same embodiment;

Fig. 3 isan exploded view (partly-sectional) to illustrate the main elements of the same embodiment, and the mannerof their assembly togetherfl .Fig. l is an enlarged sectional view of certain parts to showimore clearly how the louvres are clamped together at the frontyand Fig. 5 is an illustrative diagram to assist towards aclea'r understanding of the function of theparts. i

Referring to Figs. 1 to 4; there is provided a circular, opaquaback plate I, flanged aroundits circumference 2, and suitable for replacing the usual glass front of a'headlamp, being dimensioned to replace that front in the usual bezel. The back plate I is provided with a, rectangular orifice 3 at its "centre; and to this back plate, above the orifice '3, is spot welded a roof or cowl 4; of substantially rectangular forminplan, with the front corners rounded, and it is downwardly flanged around itsedges; the rear flange 4* being at a sharp angle and being spot welded tofthe back plate l. Thecowl is strengthened by a 'U- shaped rib 4 and has its rear flange shaped at 4 for a purpose explained below.

In front of the rectangular opening 3 in the back plate and below' the cowl 4 is the improved assembly of louvres. Each louvre 5 consists of a sheet metal pressing of substantially rectangular form, but having the outer front corners rounded to a relatively large radius. The louvres are flanged upwardly at 6' around their edges, the flange being interrupted at the rear of the side edges to form a gap 1, and the louvres each have a series of four parallel upwardly-pressed flanges 8 running from end to end, these flanges being equally spaced across the width of the louvre. Also, at the front of each louvre, there is a semicircular orifice 9, and adjacent thereto there is a projecting tongue l0, extending upwardly from the flange 6, the upper part of such tongue being of less width than is the lower part. V p The louvres 5 are assembled by the smaller end I2 2 part of the tongue [0 of one being passed into the semi-circular orifice 9 of another, and so on,

until the required number (say 10) is obtained 6. An assembly of louvres as formed is a single "composite unit, and can be handled without fear of displacement, deformation or collapse.

T There is now passed through the several semicircular openings 9 of the assembled louvres, from below, 'a stiffening member l2 which is slightly archedtransversely and is flanged at its lower The flange I2 forms an abutment against the lowermost louvre and may be welded thereto.

Spot'welded to the underside of the cowl 4, near its front edge, is a V-sectioned depending member I3; whose lower end is upturned to form a hook I4, and thehook enters the opening 9 in the-lowermost louvre 5, between the tongue I 0 and the strengthening member l2 to support the assembly from the cowl; whilst between the cowl 4 and the uppermost louvre 5-is a flat shouldered positioning member l5 having its upper end bent forward to react against the under face of the cowl, within the V-shaped member l3, and having its lower end reduced to enter the orifice 9 of the uppermost louvre'5, a'shoulder l5 reacting against the top face of the louvre. The combined result is that the several louvres 5 are clamped or vised together between these two members [3 and l 5 and are rigidly held. This is more clearly seen in Fig.- 4. 1 I Spot :welded to the back plate I, adjacent the sides 'of'the rectangular opening 3 therein,-are flanged side pieces or cheeks 16, but these are of a size not to extend so far forwardly as to reach the rounded corners of the louvres, and their forward edge isinclined to agree with the inclined front of the louvre assembly. Th side cheeks abut against the shaped parts 401 the cowl 4, at the upper rear corners.

Preferably, and as shown, there is attached to the underside of thelowermost-louvre 5, a stiffening plate H, but this will be of shorter length than the louvre so as to leave uncovered openings at the ends of the pressed-upflanges 8; through which openings any rain or other water collected in thelouvres may drain. This stiffening member l I may be aflat plate, as shown, e. g; the piece cut out of the back plate to form the orifice 3, and may be flanged along the rear edge for spot welding to the back plate. (This flange is not shown.)-

Secured to the inner face of each side plate I6, is a strip l8 having projecting hooks l9 which, as shown in Fig. 2,'encirc1e the clamping members ll. These strips are so arranged that they hold the assembly of louvres in a downwardly-inclined position relatively to the back plate, as also seen from Fig. 2. It will be seen, therefore, that the composite assembly of louvres is securely held in position at the rear corners (by the hooks l9) and at the centre front (by the members l3 and 15). The rear corners are carried on the side plates I6 which in turn are carried by the back plate, and the centre front is carried by the cowl 4 which also is carried by the back plate. Any other suitable method of mounting the rearportion of the assembly may be adopted,

allel stripes.

'co-operating either with the side plates iB,' or the cowl 4, or directly with the back'plate.-

A diffusing glass 20 will bepositione'd'behind the opening 3'in theback'platejand this maybe supported as shown by'mear'is of the strips-'21 welded'to the rear face of the backplate above and below the orifi'ce, and having theirtapered ends bent down behind the glass. Alternatively, the supporting means 2| 'maybeattached' at the sides of the rectangular opening 3, instead of at the top and bottom, and could thenbefspot welded in position onthe rear'of the back plate at the same time as are the flanged sidecheeks Iii' secured to the front'of the back plate, but in such case it would be necessary to'attach to the back plate an additional support for the; glass, below the rectangular opening, to prevent its moving downwardsbetwee'n the "members 21.

The screen 20 may comprise frosted glass,' o r, may consist of an acid-etched glass; "The-frosting or etching will'preferablybe over the whole surface of the screen, but may, as an alternative, be over' some parts'only, say for instance par- During the making-up of the device, the assembly of louvres, and the inner surface of the cowl l is sprayed with a suitable pigment to give' all the parts a matt surface and so as to be as non-reflective as possible.

Referring now to Fig. 5, the line AB represents the lower boundary of a prohibited zone into which light from the aperture is not to enter. The louvres 5 are arranged at an angle to the back plate such that the extended plane X-Y which is the plane at the greatest angle between two consecutive louvres without cutting them, will not cut the line AB. The line OP represents what would be undesired reflections but which are avoided in this invention. A consideration of Fig. 5 will show further that the upstanding flanges 6 and 8 will obstruct light passing between the louvres and will prevent many rays of light striking the upper surface of the louvres, and thereby will prevent reflection into the prohibited zone. The number of louvres, and their distance apart will vary according to the intensity of light to be emitted and to the purposes for which the light is required. A sheet of clear glass may be secured immediately in front of the louvres to exclude dust, etc.

In modified forms of the invention (notillustrated) adaptable for instance for street lighting,,the louvres in each assembly maybe of varying size. For example, the uppermost one may be the widest (i. e. may extend furthest from the light), the lowermost one may be the narrowest and those between be varied in progression. Also, instead of the sides 16 being opaque they may be cut away in part, or be transparent, to allow the emission of light sideways from the louvres. With an arrangement of this last-named kind, the louvres, in addition to inclining downwardly in a forwardly direction, may incline downwardly in transverse directions from a central transverse ridge or peak so as to have the same restricted eifect transversely as longitudinally.

The whole device will usually be made entirely of metal, either as a built-up assembly of stampings and pressings (as shown), or with parts cast and parts fabricated. Alternatively some of the parts may be of other than metal; for instance the back plate may be of thick, waterproofed card, or of wood.

"WhatIclaimis: A t 1.5 A light-screening device for-av lamp; :includ- :ing an assembly-of flat spaced louvres flanged on at'least three sides; corresponding gaps-in; said flanges-of sa'id louv'res; Uesectione'd gripping and spacing members embracing thelouvres through said gaps in the said flanges, andsecuring them together by gripping such flanges and a shaped tongue andan adjacent slot on the iront of each louvre, the tongue of one louvre passing into a slat in 'thelouvre above it to space them'at the required distanceapart 2. A light-screening-device comprising'an apertured blank, an assemblyof flat spaced louvres in front of the aperture'the louvres being flanged on at least three sides; corresponding gaps in said flanges of said louvres; U-sectioned gripping and spacing membersv embracing the louvres through the said gaps in the said flanges, and securing them together by gripping-such flanges; a shaped tongue and an adjacent slot 'on each louvre; thetongue of 'one'louvrepassing into a slot in the louvre above it to space them at the required'distance apart; a cowlsecured to the apertured blank-above the louvre assembly, side cheeks on the blank, below the cowl, to cover,

gripping and spacing members and hold the assembly in position.

3. A light-screening device'comprising an apertured blank, a cowl secured to the blank above the aperture, an assembly of flat spaced louvres below the cowl and in front of the aperture, the louvres being flanged on at least three sides; corresponding gaps in said flanges of said louvres; U-sectioned gripping and spacing members embracing the louvres through said gaps in the said flanges, and securing them together by gripping such'flanges; a shaped tongue and an adjacent slot on each louvre, the tongue of one louvre passing into a slot in the louvre above it to space them at the required distance apart; a thrust member positioned between the cowl and the uppermost louvre of the assembly, and a tension member positioned between the cowl and the lowermost louvre of the assembly.

4. For use in the head-lamp of a motor vehicle, a light-screening device comprising a circular apertured back plate flanged peripherally to fit the usual head lamp bezel inplace of the glass lens; an assembly of louvres flanged upwardly all around, the front corners of said louvres being flanged, the louvres having tongues and grooves interlinked to hold the louvres in fixed and spaced relationship at the front centre; U-sectioned clamping and spacing strips at the rear corners of said assembly; a plurality of upwardlypressed flanges formed on the louvres and adapted to prevent light falling on the top faces thereof; tapered side plates on the back plate, at least partly enclosing the louvres at the sides; hooked members in the side plates gripping theclamping and spacing grips to engage and hold the louvre assembly; a cowl on the back plate to cover over the assembly and side plates; and a diffusing glass held against the back plate behind the louvres.

5. A light-screening device including a unitary assembly of louvres of identical form, each louvre being flanged upwardly all around except fora gap at each rear corner, and each having an upstanding shouldered tongue and an adjacentthe louvre assembly, side plates extending forwardly from the blank immediately at the sides of the louvre assembly, means on the side plates to engage and'hold the U- section clamps of the assembly and means on the-cowl to engage and hold the uppermost and'lowermost louvres ofthe assembly at the front.

'7. A light-screening device comprising an assembly of spaced flat louvres of identical form each upwardly flanged except for a gap at each rear corner, the flange of each at the centre'front extending upwardly first in a wider and then in a narrower portion and each louvre having a slot immediately behind such upwardly-extending portion, the louvres being arranged with the narrower of the upwardly-extending portions entering'the slot of the next higher louvre, a stiffening member passing through the slots of all the louvres, means connecting the louvres together on their rear corners, a cowl lying over the assembly, a hook member secured. to the underface of the'cowl and hooking into the slot of the lowermost louvre and a thrust member secured to the underface of the cowl and and entering the slot of the uppermost louvre, each louvre having a number of pressed-up lips extending transversely to prevent light falling on their upper faces.

8. A light-screening device according to claim '7 and including an apertured blank shaped to fit the bezel of a motor car head-lamp in place of the usual glass, the aperture being arranged behind the louvre assembly, side plates extending forwardly from such blank, and hook means thereon to engage and hold the means connecting the louvres together on their rear corners.-.

VINCENT HARTLEY. 

